Patterned adhesives for reflectors
A reflector laminate, and backlights and displays incorporating such reflector laminates are disclosed. The reflector laminate includes a substrate and a reflector that are adhered together by a plurality of adhesive protrusions. The adhesive protrusions provide for a plurality of voids between the reflector and the substrate, so that a free reflector surface is adjacent to an air gap between the reflector and substrate. The reflector can include a multilayer interference reflector, and the presence of the air gap ensures high reflectivity for the laminate. The reflector can be adhered to a solid lightguide, a frame enclosing a portion of a backlight, a frame enclosing a hollow lightguide cavity, or an optical sheet positioned at the output surface of a backlight.
1. A backlight assembly, comprising:
a reflective laminate, comprising:
a substrate having a first surface, wherein the substrate is a back frame of the backlight;
an optically thick adhesive layer in contact with the first surface, the optically thick adhesive layer comprising a plurality of protrusions projecting from the first surface;
a multilayer interference reflector having a second surface disposed facing the first surface, wherein a first portion of the second surface is in contact with the protrusions, and a second portion of the second surface is a free surface adjacent an optically thick void;
an output element facing the multilayer interference reflector and opposite the substrate, defining a hollow cavity between the output element and the multilayer interference reflector; and
a light source capable of injecting light into the hollow cavity.
2. The backlight assembly of claim 1 , wherein the ratio of the second portion to the first portion is greater than 10.
3. The backlight assembly of claim 1 , wherein the output element comprises a partial reflector.
4. The backlight assembly of claim 3 , wherein the partial reflector comprises an Asymmetric Reflective Film.
5. The backlight assembly of claim 3 , wherein the partial reflector has an input surface and an output surface opposite the input surface, and the output element further comprises:
an optically transparent plate adhered to the output surface of the partial reflector with a second optically thick adhesive layer;
a third optically thick adhesive layer in contact with the input surface, the third optically thick adhesive layer comprising a second plurality of protrusions projecting from the input surface; and
a diffuser in contact with the second plurality of protrusions, wherein the diffuser faces the multilayer interference reflector.
6. The backlight assembly of claim 5 , wherein the diffuser is a bulk diffuser.
7. A display, comprising the backlight assembly of claim 1 or claim 5 .